Finding the Fourth Proportional to 1,705.16, 2,558.58 and 780.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,705.16 : 2,558.58 = 780.62 : x
2. Step 2: Convert to fraction form
   1,705.16/2,558.58 = 780.62/x
3. Step 3: Cross multiply
   1,705.16x = 2,558.58 × 780.62
4. Step 4: Simplify right side
   1,705.16x = 1,997,278.72
5. Step 5: Solve for x
   x = 1,997,278.72/1,705.16
6. Step 6: Final answer
   x = 1,171.31